Ivan Kőszegi (Hungarian: Kőszegi Iván, German: Yban von Güns; died 5 April 1308) was an influential lord in the Kingdom of Hungary at the turn of the 13th and 14th centuries. Earlier historiographical works also refer to him Ivan Németújvári (Hungarian: Németújvári Iván, German: Ivan von Güssing, Croatian: Ivan Gisingovac). He was Palatine in 1281, between 1287 and 1288, and from 1302 until 1307, Ban of Slavonia in 1275, from 1284 until 1285 and in 1290, and Master of the treasury in 1276 and 1291.
Originating from the powerful Kőszegi family, his career was characterized by series of rebellions and violations of the law against the royal power. As one of the so-called oligarchs, he established a province in Western Transdanubia, which laid in the borderlands of Hungary with Austria, and ruled Győr, Sopron, Moson, Vas and Zala counties de facto independently of the monarchs by the 1280s. Beside his rebellions in Hungary, he waged wars with the Duchy of Austria too. Because of his plundering and looting raids against the Styrian provinces, he was dubbed as "greedy wolf" by the Austrian chronicles. During the era of feudal anarchy, he usually played a role of "kingmaker". For instance, he invited Andrew the Venetian to the throne against the reigning Ladislaus IV of Hungary three times (1278, 1287, 1290). He initially supported Andrew III after his accession to the throne, but from 1292 he turned against the king and became a partisan of the pretender, Charles Martel, Duke of Salerno. After the extinction of the Árpád dynasty in 1301, he betrayed the House of Anjou too and played an important role in the subsequent succession war as the partisan of Wenceslaus, then Otto.
